Wideband Antenna Ground Plane Optical Reflector Missile

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Solution Overview

Problem

The challenge is to design RF antenna systems that can operate within a small physical volume while maintaining wideband RF performance, particularly for applications like missiles and other small platforms where space is limited and bandwidth demands are increasing, including lower frequency operations.

Innovation Solution

The solution involves a compact antenna structure with a ground plane that also acts as an optical reflector, allowing for the collocation of RF and optical transducer systems within a small volume. This includes using a ground plane with an opening for optical signals and a secondary dielectric or metamaterial reflector to minimize RF coupling, enabling wideband RF performance from 0.65 GHz to 5 GHz within a diameter of 2.75 inches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the antenna is made compact to fit within limited space, then the volume is reduced, but the RF bandwidth performance deteriorates

Engineering Contradiction:
Improveantenna volumeVSAvoidRF bandwidth
Core Design Contradiction:
Volume of moving objectVSAdaptability or versatility

Solution Approach 1:

The patent combines the optical reflector and RF ground plane into a single integrated structure. The reflective surface serves dual purposes: reflecting optical signals for the electro-optical sensor while simultaneously acting as the ground plane for RF antenna elements. This merging allows both optical and RF systems to share the same physical space, enabling compact implementation without compromising RF bandwidth performance.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The reflective surface is designed to perform multiple functions simultaneously: it acts as an optical reflector for the electro-optical sensor and as a ground plane for wideband RF antenna operation. This multi-functionality allows the system to achieve both optical and RF capabilities within a compact volume, resolving the contradiction between size reduction and bandwidth maintenance.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Volume of moving object

If RF and optical transducer systems are collocated within a small volume, then the system size is reduced, but RF performance may be degraded due to interference

Engineering Contradiction:
Improvesystem volumeVSAvoidRF performance
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

A dielectric substrate is introduced as an intermediary between the reflective surface and the RF antenna elements. This dielectric layer acts as a mediator that allows the reflective surface to function as both optical reflector and RF ground plane while minimizing unwanted coupling between the optical and RF systems. The dielectric material enables close integration without degrading RF performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent positions RF antenna elements at specific locations away from the center of the reflective surface, where they can access the ground plane without interfering with the optical path. This local placement strategy allows different parts of the system to have optimized properties: the center region maintains optical reflectivity while peripheral regions provide RF ground plane functionality.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If multiple radiating elements are added to support multiple RF applications, then the functionality is improved, but the device complexity increases

Engineering Contradiction:
ImproveRF application supportVSAvoidantenna structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Multiple RF radiating elements are integrated onto the same ground plane structure that also serves as the optical reflector. This merging approach allows multiple antenna elements supporting different RF applications (communications, GPS, radar) to share the common ground plane, thereby increasing functionality without proportionally increasing overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach allows for compact implementation of RF systems with wideband RF performance, supporting multiple RF applications like communications and radar tracking without increasing the system size, and enables the addition of optical functionality without degrading RF performance.

Implementation Method 1

the ground plane is an optical reflector in the optical transducer subsystem

Methodology Applied
Scientific EffectOptical reflection: Reflection

Implementation Method 2

multiple radio frequency (RF) radiating elements disposed adjacent to a ground plane

Methodology Applied
Scientific EffectElectromagnetic ground plane effect: Electromagnetic Induction

Data Source

PatentEP3221921B1Wideband antenna structure with optics reflector as ground plane for missile applications
Publication Date: 2019.01.09 RAYTHEON CO
  • EP3221921B1 patent drawingFigure 1~2
  • EP3221921B1 patent drawingFigure 3A~3C
  • EP3221921B1 patent drawingFigure 4~5

AI summary

A compact transducer system includes both an antenna subsystem and an optical transducer subsystem. The antenna subsystem may include multiple radio frequency (RF) radiating elements disposed adjacent to a ground plane. The ground plane may also serve as an optical reflector within an optical path of the optical transducer subsystem. A secondary reflector may also be provided within the optical path of the optical transducer subsystem. The secondary reflector may be formed of dielectric material (e.g., meta-material) in some embodiments to prevent undesired coupling with RF circuitry.